This invention relates to a paper feeding cassette for a printing apparatus. More particularly, this invention relates to a cassette which stores and supplies paper to a printing appratus which may be either a printer connected to a computer or a copier. In the case of a printer connected to a computer, the printing apparatus produces originals on a sheet of paper. In the case of a copier, the printing apparatus reproduces an original on a sheet of paper.
With the recent surge in numbers and kinds of small computers that are available in the marketplace, there has come also a surge in the number and kinds of printers that can be connected to them. Today, among the different kinds of printers which can be interfaced to small computers are: dot matrix printers, daisy wheel printers, ink jet printers, electrographic printers, etc. Many advances have been made in the capabilities of these printers. The more advanced of these printers, contain their own internal computers or controllers which communicate information to the host computer and/or the user. For example, these printers are capable of diagnosing malfunctions and formatting the manner in which data is to be printed. Such printers, having their own internal computers, are often referred to as "smart" printers.
Similar advances have been made in copiers. Today, many of the copiers which are available on the market have their own internal computers. These internal computers are also able to diagnose and inform the user of any malfunction. In some instances, the copier is provided with detection means for detecting the size of the original. The internal computer can then make the appropriate adjustments so that the original is copied on the right size paper, for example, by selecting the cassette from which the paper will be taken. Such copiers may be referred to as "smart" copiers.
The present invention provides an improvement over prior art "smart" printers and copiers. Heretofore, in the case of prior art printers, it has been necessary for the user to input formatting information to the external computer. The external computer would then communicate this information to the smart printer's internal computer and the page would be printed with the proper format. For example, in order to achieve proper formatting, it was necessary for the user to specify the size of the paper in the paper cassette to the external computer. If this information were not communicated to the external computer, the printer would print on whatever size paper appeared in the paper cassette tray. This could lead to mistakes in formatting.
Similarly, problems could arise in the case of a smart copier. While it was not always necessary to input the paper size when one wanted the copy to be the same size as the original, the situation was otherwise when one wanted to make a copy of a different size. It was often necessary to "inform" the copier on which size paper to copy the original if one wanted to increase or decrease the size of the original. This was done by pressing the appropriate buttons on the console of the copier. In some cases, the copier or the printer was able to select paper of different sizes from different cassettes. However, no means were provided for the copier to adjust the size of the copy in response to the size of the paper in the paper input tray.
Thus, in prior art printers and copiers, including smart printers and copiers, it was necessary to conform the cassette or the paper in the cassette to the selected paper size. No means were available to automatically format the paper size without the intervention of the operator.
These problems are overcome by means of the present invention. In accordance with the present invention, it is no longer necessary for the user to manually input the paper size to the printer or the copier. The present invention provides means by which the smart printer or smart copier, as the case may be, senses the size of the paper which is loaded into the paper supply tray. This information is communicated to the internal computer in the smart printer or smart copier. Appropriate adjustments can then be made in the printer or copier so that the image formed on the paper is properly formatted without the need for the user to specify the paper size.